Hollow core molding machine



R. W. TACCONE HOLLOW CORE MOLDING MACHINE March 17, 1959 2 Sheets-Sheet l FIG.

Filed April 4, 1956 Fig.2

IN VEN TOR.

March 17, 1959 R w. TACCONE HOLLOW CORE MOLDING MACHINE 2 Sheets-Sheet 2 Filed April 4, 1956 INVENTOR.

United States Patent HOLLOW CORE MOLDING MACHINE Russell W. Taccone, Erie, Pa., assignor to Taccone Pneumatic Foundry Equipment Corporation, North East Township, Pa., a corporation of Pennsylvania Application April 4, 1956, Serial No. 576,134

3 Claims. (Cl. 22-10) This invention relates to foundry equipment for making hollow articles and more particularly to equipment for making hollow cores for use in casting pipe sections, branch fittings, and the like.

In the manufacture of cast iron pipe such as soil pipe, an important part of the manufacturing technique is the making of cores. In making cores, a problem is encountered in forming the internal surface of the pipe. If the cores remain solid, they are heavy to handle and a large amount of core material is utilized. If the cores are hollow, manufacturing problems are encountered in making the cores.

In carrying out the present invention, a resilient tubular diaphragm-like mandrel is inserted into a core box, the core box having the shape of the outside of the finished co're. Sand is then put in around the mandrel and compressed air is admitted into the mandrel whereby the sand is compressed into intimate contact with the inside of the core box. The air pressure can then be released and the mandrel removed. The core box can then be opened and the core removed.

Accordingly, it is an object of this invention to overcome the defects and disadvantages in prior methods and apparatus for making cores and, more particularly, it is an object of this invention to provide a method and an apparatus for manufacturing hollow cores which is simple in construction, economical to manufacture, and simple and efiicient in operation.

Another object of this invention is to provide a method of forming hollow cores.

Another object of the invention is to provide a method and apparatus for forming hollow cores for cast iron elbows.

A further object of the invention is to provide a method for forming hollow cores for making branch fittings.

A still further object of the invention is to provide a method of making curved hollow cores for use in metal castings.

With the above and other objects in view, the present invention consists of the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawings and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions, and minor details of construction without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawings:

Fig. 1 is a view of a machine for making a hollow core for a cast iron elbow;

Fig. 2 is a view of the machine shown in Fig. 1 having the mandrel removed therefrom;

Fig. 3 shows another embodiment of the invention, that is, a similar machine used for making branch fittings showing the diaphragm in expanded position;

Fig. 4 is another embodiment of the invention showing a core with sand therein and the upset in place;

2,877,521 Ce Patented Mar. 17,1959

Fig. 5 shows the core box shown in Fig. 1 with the upset removed;

Fig. 6 shows the mandrel having the diaphragm expanded; and

Fig. 7 is an isometric view showing the finished core being removed. "I

Now with more specific reference to the drawings, Figs. 1 and 2 show a machine for making hollow cores for cast iron soil pipe elbows. A core box 10 is provided, preferably made in two separable halves, one half ofthe core box 10 being shown with the diaphragm and sand shown in cross section thereon. Integral with the core box 10 are formed ears 11. A bracket 12 is pivoted at 13 and is swingable therearound. A collar 14 is at: tached to the bracket 12 concentric with an aperture 15 which communicates with a hose 16. Inside the collar 14 and concentric therewith is attached an arcuate hollow mandrel 18 which is fixedly attached to the bracket 12 at 19 and extends therefrom in an arcuate path centered at the pintle point 13. p .1

A resilient tubular closed ended diaphragm 20 is sealed between the collar 14 and the end of the mandrel 18 adjacent the end 19. The diaphragm 20 in its relaxed position lies in intimate contact with the mandrel 18. Spaced apertures 21 are disposed aroundand through the body of the mandrel 18 and communicate from the inside of the mandrel 18 to the inner surface of the diaphragm 20. The core box 10 will ordinarily have the mandrel 18 inserted therein in the manner shown in Fig. 1, the mandrel 18 being in unexpanded position. The core box 10 will then be filled with sand and the top half put in position and clamped. Then air under PIES! sure will be inserted through the hose 16 and it will expand the mandrel 18 in the manner shown in Fig. l which will pack the sand into intimate contact with the inner surface of the core. The pressure on the hose 16 can then be removed and the resilience of the diaphragm 20 will return it to its intimate contact position with the mandrel 18.

In order to aid the diaphragm 20 in returning to its original position, a vacuum can be imposed on the hose 16 which will react through the apertures 21 to draw the diaphragm 20 into intimate contact with the mandrel 18. The core can then be heated or treated by any desired method to harden it and the two halves of the core box 10 will then be separated and the core removed therefrom and the operation repeated.

Fig. 3 shows another embodiment of the invention wherein the lower half of a mold box is shown having sand 111 therein. The operation of a mandrel 118 is very much like the operation of the mandrel 18 shown in Figs. 1 and 2; however, the mandrel 118 in this case is straight, not curved, and is removed by withdrawing'it from the cavity in the mold, not swinging it about a point as the mandrel 18 in Figs. 1 and 2. The mandrel 118 has apertures 121 therethrough and has a closed ended tubular diaphragm attached to a flange 112 between a collar 114 and the mandrel 118. A similar collar 212 is attached to the mold box 110 at 213 and has an air tube 216 attached thereto. The collar 212 has a collar 214 attached thereto and a mandrel 218 is attached-to the collar 214 with a diaphragm 220 therebetween.

During operation, the mandrels 118 and 218 with the diaphragms 120 and 220, respectively, relaxed to intimate contact with the mandrels 118 and 218, are inserted into the mold box 110 and the sand 111 packed therearound. Then the top half of the mold box 110 which is a counterpart of the upper half of the mold to be formed is put in place and clamped. Air pressure is then applied through the air tubes 116 and 216 which will expand the diaphragms 120 and 220, respectively, to the position shown in Fig. 3. The air pressure can then be relieved,

This will relax the diaphragms 120 and 220 out of engagement with the sand 111 and the diaphragms 120 and 220 with the mandrels 118 and 218 and collars or flanges 112 and 212 can be withdrawn. Then the two halves of the mold box 110 can be separated and the finished mold removed.

In Figs. 4, 5, 6, and 7, still another embodiment of the invention is shown wherein a hollow core can be formed. A lower half 310 of the core box has a cavity 311 therein which conforms to the lower half of a core of a fitting to be made. An upset 312 is swingably attached at 313 to the lower half 310 of the core box and an upper half 314 is swingably attached to the lower half 310 at 315. An upper half cavity 316 is formed in the'upper half 314 of the core box. A mandrel 317 has a hose 340 and a resilient closed ended tube or diaphragm 321 attached thereto similar to the hose 216 and collar 212 shown in Fig. 3.

- During operation, the operator will swing the upset 312 to the position over the bottom half 310 as shown in Fig. '4. The mandrel 317 will be inserted in place concentric with the cavities made up of the cavities 311 and 316 and the upset 312 will be filled with sand 320 as shown. The upset 312 will then be swung to the position shown in Fig. 4 and a hopper 319 with the sides thereof extends downwardly and outwardly. The sand 320 will lie loosely in the upset 312 but if the sand 320 has a proper binder therein, it will hold the shape of the upset 312 shown in Fig. 5 while the upper half 314 of the core can then be swung into position and, when in the position shown in Fig. 6, air pressure can be applied to the inside of the mandrel 317. The air will flow through the hose 340 and the air pressure will expand the diaphragm 321 as shown in 'Fig. 6 to pack the sand 320 into intimate contact with the inside of the core box. The upper half 314 of the core can then be swung back to the position shown in Fig. 4, the mandrel 317 removed, and the finished core removed as shown in Fig. 7.

The foregoing specification sets forth the invention in its preferred practical forms but the structure shown is capable of modification within a range of equivalents without departing from the invention which is to be understood is broadly novel as is commensurate with the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A molding machine comprising a mold box having a cavity therein, said cavity extending from one outside edge of said mold box inwardly, said cavity in said mold box having an outside surface conforming to the shape of a core to be manufactured, a hollow mandrel adapted to-be inserted into said cavity generally concentric therewith, a tubular flexible diaphragm adapted to be expanded to form the inside surface of a core to be manufactur'ed, said diaphragm disposed on said mandrel and attached thereto at one end thereof and closed at the other end thereof, an aperture in said mandrel providing an air passage to admit compressed air to the space between said diaphragm and the outside of said mandrel, said cavity in said mold box around said tube adapted to receive molding material, said diaphragm adapted to be expanded by compressed air to compress said molding material into intimate engagement with the material for forming the outside surface of said cavity, said diaphragm being made of resilient material and, in unexpanded relation, resting in intimate relation with the outside surface of said mandrel, said mandrel being curved, and a lever connected to said mandrel and to said mold box at the center of curvature of said mandrel whereby said mandrel may swing in and out of said cavity in said mold box in a well defined path.

2. A molding machine comprising a mold box having a cavity therein, said cavity extending from one outside edge of said mold box inwardly, said cavity in said mold box having an outside surface conforming to the shape of a core to be manufactured, a hollow mandrel adapted to be inserted into said cavity generally concentric therewith, a tubular flexible diaphragm adapted to be expanded to form the inside surface of a core to be manufactured, said diaphragm disposed on said mandrel and attached thereto at one end thereof and closed at the other end thereof, and an aperture in said mandrel providing an air passage to admit compressed air to the space between said diaphragm and the outside of said mandrel, said cavity in said mold box around said tube adapted to receive molding material, said diaphragm adapted to be expanded by compressed air to compress said molding material into intimate engagement with the material for forming the outside surface of said cavity, said cavity in said mold box being arcuate in shape and said mandrel being swingably connected to said mold box at a point at the center of curvature of said cavity in said mold box.

3. A molding machine comprising a mold box having a cavity therein, said cavity extending from one outside edge of said mold box inwardly, said cavity in said mold box having an outside surface conforming to the shape of a core .to be manufactured, a hollow mandrel adapted to be inserted into said cavity generally concentric therewith, a tubular flexible diaphragm adapted to be expanded to form the inside surface of a core to be manufactured, said diaphragm disposed on said mandrel and attached thereto at one end thereof and closed at the other end thereof, and an aperture in said mandrel pro vidiug an air passage to admit compressed air to the space between said diaphragm and the outside of said mandrel, said cavity in said mold box around said tube adapted to receive molding material, said diaphragm adapted to be expanded by compressed air to compress said molding material into intimate engagement with the material for forming the outside surface of said cavity, said mold box having two openings through the sides there of communicating with said cavity in said mold box, the inside of said material defining said cavity defining a Y- shaped member, one said mandrel with one said diaphragm thereon being adapted to be inserted into each said opening, one said diaphragm terminating adjacent the side of the other said diaphragm.

References Cited in the file of this patent UNITED STATES PATENTS 47,937 Davis May 30, 1865 273,095 Johnson Feb. 27, 1883 381,645 Rieth Apr. 24, 1888 720,718 Maddock et al Feb. 17, 1903 799,847 Hay Sept. 19, 1905 1,154,238 Drysdale Sept. 21, 1915 1,795,370 Lukomski Mar. 10, 1931 2,052,818 Freyssinet et a1. Sept. 1, 1936 2,651,088 Williamson et al Sept. 8, 1953 FOREIGN PATENTS 527,222 Germany May 28, 1931 

